Tuesday, November 3, 2009

After air travel security banned bottled water andbaby formula, I began wondering why they didn'tuse a device to determine the contents of liquids. If aliquid was detected to be safe, security could allow iton the plane. Spectrometers can identify the chemi-cal makeup of a material by shining light on it andanalyzing the precise mix of colors that bounce back.

These devices are usually very expensive, butI've designed a simple and inexpensive one that canidentify liquids. You can also adapt it to determinethe color of a swatch of paper or cloth or to identifya gem or semiprecious stone.

I spent less than $100 on this project and it tookjust a few days to design, fabricate, and test the hard-ware, plus another two days to write and debug thesource code. Collecting the liquids and building thedatabase took one evening, and it was fun!...